From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D64F02D9484; Sun, 9 Aug 2026 02:32:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786242737; cv=none; b=TyWajyd4qS7Uz7F0NOuY7e9ASTnAf95grv02oKySbr/GTgmVX/HwFyM+WiQR85ctKMgoAeVKTbXdkfhKiXwSDv5v5kG9escUhpbTA/EXh/5JnrIiN89lDlvHD0lUvJc+9rCmpapr5jiiFAofqlj+749bFcXvHFmekx4dNU6KLO8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786242737; c=relaxed/simple; bh=oiqWJDC2i3077dMUP6JnqZ64oRUCFp35NaNbNec2s6U=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=b8aYcXJtvjjnJQmKywKthe3TAbCmCQSxH61dOgZ26kYqbl3mBZ2n+Lgq4wS7WYHpbjQHuFphiA+A6emkGqtrf3msRxpnR070Sf9Nwmg8eGlhC9Ftg5sMVj3goWr2irUFamoZ0IK3DGv/OkVGPlTIU6mvAguc5Bf8z9EX68+1xN8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YVbK13Ow; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="YVbK13Ow" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9C5871F00ADB; Sun, 9 Aug 2026 02:32:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786242735; bh=PGNsOxfqDTW8bFGdBdNdVIBp6Eh0qzmzMbRY+9D8jJc=; h=Date:From:To:Cc:Subject:References; b=YVbK13OwH0iis+bCQhTOas5moKgfbeKqTezJe3A3WWK+H2jrOLwXpEloj3U6Eq6vr FS+f0RROLAn+YanT1P4kMZWqn9+AjjhoyPZHmE55syMy8DVc+1ZfgeLGQaHc/Ku2TP csIbIZtydQRREF7pZBGk85g+zfwWI1TpifHN6pyCWu38HbJNu+rdXelnS2y0JMkvGe zXSJeySqDwhmSTOMNVcJJcFqCxVjbPs8JDZ5p2a1sv7XFDW+juprI3J0dRtDBOq1FE TndFR6KuTRSawT5lOxcUgWwQNzVQ6+h5ZpJ2G8ZKG3FefRfW8aheLLbiX8ncaN6wuv SADX57NkWDs3g== Received: from rostedt by gandalf with local (Exim 4.99.4) (envelope-from ) id 1wstKn-00000001N4D-4BNk; Sat, 08 Aug 2026 22:32:21 -0400 Message-ID: <20260809023221.854869492@kernel.org> User-Agent: quilt/0.69 Date: Sat, 08 Aug 2026 22:31:48 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , stable@vger.kernel.org, Jiri Olsa , Leon Hwang Subject: [for-linus][PATCH 04/12] ftrace: Protect direct_functions in update_ftrace_direct_del References: <20260809023144.852271250@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 From: Leon Hwang Fix accessing the __rcu pointer direct_functions with RCU protection. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260730150411.88667-3-leon.hwang@linux.dev Fixes: 8d2c1233f371 ("ftrace: Add update_ftrace_direct_del function") Acked-by: Jiri Olsa Signed-off-by: Leon Hwang Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index c5d1d0d42ccc..9ea39110927f 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -6512,6 +6512,7 @@ int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace_hash *hash) struct ftrace_hash *new_direct_functions; struct ftrace_hash *new_filter_hash = NULL; struct ftrace_hash *old_filter_hash; + struct ftrace_hash *direct_hash; struct ftrace_func_entry *entry; struct ftrace_func_entry *del; unsigned long size; @@ -6523,11 +6524,13 @@ int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace_hash *hash) return -EINVAL; if (!(ops->flags & FTRACE_OPS_FL_ENABLED)) return -EINVAL; - if (direct_functions == EMPTY_HASH) - return -EINVAL; mutex_lock(&direct_mutex); + direct_hash = rcu_dereference_protected(direct_functions, lockdep_is_held(&direct_mutex)); + if (direct_hash == EMPTY_HASH) + goto out_unlock; + old_filter_hash = ops->func_hash ? ops->func_hash->filter_hash : NULL; if (!hash_count(old_filter_hash)) @@ -6537,7 +6540,7 @@ int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace_hash *hash) size = 1 << hash->size_bits; for (int i = 0; i < size; i++) { hlist_for_each_entry(entry, &hash->buckets[i], hlist) { - del = __ftrace_lookup_ip(direct_functions, entry->ip); + del = __ftrace_lookup_ip(direct_hash, entry->ip); if (!del || del->direct != entry->direct) goto out_unlock; } @@ -6548,7 +6551,7 @@ int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace_hash *hash) if (!new_filter_hash) goto out_unlock; - new_direct_functions = hash_sub(direct_functions, hash); + new_direct_functions = hash_sub(direct_hash, hash); if (!new_direct_functions) goto out_unlock; @@ -6575,7 +6578,7 @@ int update_ftrace_direct_del(struct ftrace_ops *ops, struct ftrace_hash *hash) /* free the new_direct_functions */ old_direct_functions = new_direct_functions; } else { - old_direct_functions = direct_functions; + old_direct_functions = direct_hash; rcu_assign_pointer(direct_functions, new_direct_functions); } -- 2.53.0